Bought a Vevor 3018 Pro a year back, and got the S4040 because I was ready for bigger items. It's neat.
Pros (lots):
The price is very accessible. Shipped fast, well packaged. It is pretty to look at, nice trim colors, superb spindle for the money, very quiet! The 300W spindle is why I chose this over others, along with my prior experience with VEVOR. It has an offline controller, which is how I run it, the other reason I got this model (I much prefer an offline controller, and the full size SD carrier for the microSD makes using with my computer much easier!) . Comes with 4 clamps. A large working area slightly bigger than 15.7" x 15.7", depends on belts and limit switch for absolute size. Did I say it has limit switches? Didn't expect them, but there they are. Super. Has a nice control box. Assembly was straightforward. Take your time. Make sure all is square, and aligned. Tighten with care, evenly. No problems.
Cons (not many):
-Could use an instruction manual for the offline controller.
--Be careful that your control box Emergency Stop isn't locked down on receipt, it may confuse you that it is not working. Rotate to unlock it, then reset the alarms in the offline controller.
--I had one Z limit switch wire that arrived disconnected or got that way somehow during assembly. Once that was corrected, along with the emergency button reset, all worked *perfectly*.
Summary: This cuts well, and quickly. I can go faster than my 3018 if I wish, and it's quieter too. I *love* the larger area. And this CNC can be made even larger with a minimal investment. Did I say I liked the colors? It is a thing of beauty.
Only thing I'd change as to aesthetics would be just to have VEVOR alone on the controller box, the ad copy isn't needed for a CNC. Not a biggie. :) I really like this so far. And I know from the one problem I had with my 3018 well into the warranty period that VEVOR will have me covered. Shipping was fast by the way, only a few days. WELL packaged. Just wish there was an official user manual for the offline controller covering all aspects of that, only reason I gave 4 stars for easy to use, vs 5 for that one category. Very impressed with this. A fine value. Am glad this is available.
Extra Notes: Set your Z carefully, life will be good. Make sure clamps clear the Z axis for any motion, only problem I had once was I had a clamp slightly in the way and lost a step or two -- my fault, just due to learning this one. Screw them down as low as possible.
You will want a sturdy table to run this on, particularly if working it at speed, and make sure it is secured well (it can go fast). Has rubber feet (another great addition). Again, this thing's working area is so much nicer for all the new craft boards and surfaces you can find locally or online. Perfect for them, no more having to worry about space on the 3018 Pro. :) See pics.
Artly There 
